1. Field of the Invention
The present invention relates to a portable computer and, more particularly, to a portable computer with a power control function.
2. Description of Related Art
The management of the power supply of a notebook computer is quite important because notebook computer users are more and more critical on the characteristic of mobility. The power supply of a notebook computer includes two parts, namely, the system power supply for the main unit and the power supply for the LCD display.
In many circumstances, a notebook computer user needs only to use the main unit of the notebook computer without using the LCD display. For example, when making a brief presentation, the user may connect a projector to the notebook computer to display the content of the brief presentation by projection. At this time, the notebook computer operator needs not to use the LCD display of the notebook computer. However, the LCD display of the notebook computer may still in action, wasting much power supply.
Notebook computers with a cover switch or magnetic switch to control the power supply for the LCD display are commercially available. When the user needs not to use the LCD display, the user can close the LCD display of the notebook computer to drive the cover switch or magnetic switch, thereby turning off the power supply for the backlight module.
The aforesaid cover switch or magnetic switch has numerous drawbacks. The use of a cover switch in a notebook computer obstructs the sense of beauty of the notebook computer's outer appearance. Further, the mechanical cover switch may malfunction when by an external force deforms the LCD display of the notebook computer accidentally. If a magnetic switch is used in a notebook computer, it acts subject to a predetermined Gauss value between magnets. However, it is difficult to control the generation of the predetermined Gauss value between magnets, and the distance detected by the sensor of the magnetic switch may change. Further, the Gauss value may attenuate after a long use of the magnetic switch, resulting in a control error. In this case, the magnetic switch may switch off the power supply of the backlight module of the LCD display erroneously when the notebook computer is kept opened.